OTTAWA - Police tactics to root out marijuana grow ops by using infrared aerial surveillance do not contravene the constitutional right to privacy in one's home, the Supreme Court of Canada ruled Friday.

The decision is in contrast with the law in the United States, where the high court ruled three years ago that it is unconstitutional for police to use the thermal heat cameras without a judge's warrant because of the need to protect the home "from prying government eyes."

The Canadian Supreme Court unanimously concluded that the cameras, which are used to detect external "hot spots" that may indicate the presence of electricity-gobbling marijuana growing operations, are "non-intrusive" and "mundane" in the information that they reveal.

The decision is a loss for handyman Walter Tessling, who said police violated his Charter of Rights protection against unreasonable search by unlawfully using an infrared aerial camera over his home near Windsor, Ont.

The ruling restores his conviction and sentence of 18 months in jail for being caught with 120 marijuana plants.

"Living as he does in a land of melting snow and spotty home insulation, I do not believe that the respondent had a serious privacy interest in the heat patterns on the exposed external walls of his home," Justice Ian Binnie wrote in the 7-0 decision.

"Safety, security and the suppression of crime are legitimate countervailing concerns."

Police, who are already losing the war against hydroponic marijuana operations, warned the Supreme Court that requiring warrants to use heat-sensing cameras would lead to "investigative gridlock."

The Supreme Court rejected a ruling from the Ontario Court of Appeal that the surveillance technique merits a warrant because the detected heat may come from "perfectly innocent" private activities, such as taking a bath or using lights at unusual hours.

"The nature of the intrusion is subtle but almost Orwellian in its theoretical capacity," said the 2003 ruling, authored by Justice Rosalie Abella, who was then on the appeal court but has since been promoted to the Supreme Court.

Binnie confined the court's ruling to the infrared technology as it exists today and said that any advancements will have to be dealt with by the courts.

Despite Tessling's loss, his lawyer, Frank Miller, believes the Supreme Court has a pattern of siding with privacy rights over police powers.

Miller also noted that new infrared technology that exists in the U.S.

-- which can detect people moving in their homes -- would probably not survive a Canadian legal challenge.

He based his conclusion on the tempered nature of the Supreme Court ruling, which repeatedly stressed that privacy is paramount and "that the spectre of the state placing our homes under technological surveillance raises extremely serious concerns."

The Supreme Court ruled 10 years ago that police can freely obtain electricity bills in their investigations because they reveal little about personal lifestyles and, therefore, do not meet the test for privacy protection.

With 173 marijuana grow operations busted by York cops in 2003 and more than 100 raided so far this year, Chief Armand La Barge said the ability to use infrared technology without going to a judge first will help hundreds of investigations.

The infrared camera, a large round device that sits on the front of the helicopter and feeds images of heat sources to a screen inside the cockpit, has sat dormant since January 2003 when the Ontario Court of Appeal overturned the drug conviction of a Windsor man, forcing police across the country to obtain warrants before using the technology.

The court found infrared images constituted a search under the Charter of Rights and Freedoms and police should have obtained a warrant prior to using it.

Since then, York Regional Police have only obtained a warrant for the use of infrared images a few times.

"If you could get a warrant to use (infrared), you could get a warrant to search the house. So, at that point, why bother?" said flight officer Yvon Roach.

Last week, the Supreme Court of Canada overturned the decision opening the door to a more liberal use of the technology. It's a door York Regional Police are happy to be walking through.

"We're definitely going to use it a lot more now," added flight officer Boris. "We're very pleased."

However, in using the technology, police may be trampling all over the Charter of Rights and Freedoms, one York Region legal expert said.

"I see it as an invasion of privacy," Aurora criminal lawyer Barry Switzer said. "The police and the courts may say I'm comparing apples to oranges here, but it seems like there is a video camera on you at all times these days, every phone call you make, there some disclaimer that comes on telling you this call may be monitored. It's Big Brother turned on its head."

While they can detect high sources of heat, infrared cameras cannot determine the exact nature of the source.